In the recent past, modular telephone connectors have become established in telephone systems. These connectors typically are used in interconnections between a telephone handset and a telephone body, and between a telephone and a telephone service wall outlet. To comply with a service standard, a modular connector plug typically must withstand at least one thousand insertions into a mating socket or jack without destructive wear on a low resistance gold layer on the contact surfaces of the plug and its respective jack.
It is known that the life span of a gold layer plated over a smooth surface of a base metal is greater than that of a similar gold layer plated over a relatively rougher base metal surface when both gold layers are subjected to similar frictional engagements with mating surfaces. A problem exists, however, in applying this knowledge in a useful and efficient manner to the manufacture of small articles, such as contact blades for the aforementioned modular telephone connectors.
When an electrolytic etching process, referred to as electropolishing, was used to smooth the contact edge of the blade, it was found that a sufficient electrolytic action to smooth the contact edge of the blade also attacked the already smooth sides of the blade to thin the blade and thereby to deform and weaken the blade. The electrolytic polishing action became especially detrimental when a strip of a plurality of such contact blades was moved through an electrolytic bath.
The above attempt to electropolish the contact blades involved a submersion of the articles to be treated into the electrolytic bath. In some special electrolytic treating processes, however, articles are only partially submersed into the electrolyte. For instance, in the manufacture of contact wires for diodes, crystal rectifiers and detectors, it is desirable to form a point on a wire. The point contacts and establishes a rectifying contact with a semiconductor or other crystal element. In forming the point, the submersed portion of the wire is uniformly attacked and electrolytically dissolved except near the surface of the electrolyte where the electrolytic action in a meniscus is known to decrease until it stops at the surface. It is adjacent the meniscus of the electrolyte, where the desired point on the wire forms.
This described concept has in the past been applied in a process involving inserting a metal blade partially into an electrolytic etching bath to form a tapered edge along the blade by dissolving the metal extending into the electrolytic bath. The process consequently permits tapering the metal blade near the surface of the bath. However, such a tapered edge is undesirable on the described connector blade in that such a tapered edge tends to laterally displace and jam against a mating wire contact. Also, a reduced contact area at the edge of a tapered cross section tends to increase the contact force per area and thereby increase the frictional wear on the contact.